If x₁: y₁ and x₂: y₂ are in direct proportion, then choose the correct relation from the following.
 

If two ratios are equal, they are said to be in direct proportion.
Therefore, x₁: y₁ = x₂: y₂
$\frac{{\mathrm{x}}_1}{{\mathrm{y}}_1}= \frac{{\mathrm{x}}_2}{{\mathrm{y}}_2}$
⇒ $\frac{{\mathrm{x}}_1}{{\mathrm{x}}_2}= \frac{{\mathrm{y}}_1}{{\mathrm{y}}_2}$
This can also be written as: x₂ × y₁ = x₁ × y₂